1. Field of Invention
The present invention relates to methods and devices for image processing and more particularly, to methods and devices for brightness control of images in display devices.
2. Description of Related Art
In a color display monitor or a color television, if a flat-panel display is used, it is easier to increase the screen size. But the brightness of displayed images is decreased in comparison with the use of a cathode-ray tube. To overcome such a drawback, a four-color output device in which a white color component is added to the three primary colors of RGB (Red, Green, and Blue) is employed. The white color component can be obtained by having a white light transmitted or reflected onto a white filter, which increases the overall brightness of the images in display devices.
A side effect of adding the white color component to the original three primary colors to increase the brightness of images is the decrease in color saturation. To overcome the side effect, the original three primary colors need to be adjusted, so that when these adjusted RGB colors and the white color component are outputted together, the brightness can be increased while the color saturation is almost kept.